I would never leave power steering on a performace
Mustang. My 67 Shelby came with PS and I replaced it with
manual and lowered the front upper pivots according
to the Boss 302 Chassis Manual. I have mine set as my
65 Shelby, 2 Degrees Caster, 0 Degrees Camber and 1/8"
Toe In. Drives like a charm and I have never had any problems
with tire wear. If you go negative on Camber you will most
likely see increased tire wear. To replace a PS on a 67 to
manual is very easy, pitman, idler and steering link
only. To do the same on a 65/66 I believe you need new tie rods as well if I don't recall wrong.
Good luck, Bo